Depends what breed.
Old English Sheepdogs were bred for stamina, to drove herds log distances along roads to market.
Border Collies are meant for herding up and controlling flocks, they are bred for brains more than anything. They show 'rounding up' behaviour even when not trained for it.
There's an Italian bred of sheepdog that's bred to look just like a sheep from a distance, they are hard to spot in a flock. they are bred to live out with the sheep in all weathers, the protect them from wolves and thieves.
So, their job description can vary a bit.
Akbash Dog
Alpine Shepherd Dog
Anatolian Shepherd Dog
Appenzeller Mountain Dog
Australian Kelpie
Australian Shepherd
Bearded Collie
Beauceron
Belgian Laekenois
Belgian Malinois
Belgian Sheepdog
Belgian Tervuren
Bergamasco
Border Collie
Bouvier des Flandres
Briard
Canaan Dog
Cardigan Welsh Corgi
Carpatin
Catahoula Leopard Dog
Catalan Sheepdog (Gos d'atura)
Central Asia Shepherd Dog (Sredneasiatskaia Ovtcharka)
Ciobănesc de Bucovina
Collie (a broad type of many related breeds)
Coolie Dogs
Croatian and Bosnian Tornjak
Croatian Sheepdog
Dalmatian
English Shepherd
German Shepherd Dog
Greek Tsopanoskylo
Kuvasz
Huntaway
Himalayan Sheepdog
Kangal Dog
Komondor
Koolie
Icelandic Sheepdog
Labrador Retriever
Maremma Sheepdog
Mioritic
Mudi
Norwegian Buhund
Old English Sheepdog
Pembroke Welsh Corgi
Picardy Shepherd (Berger Picard)
Polish Lowland Sheepdog
Puli
Pyrenean Mountain Dog (Great Pyrenees)
Pyrenean Shepherd
Rough Collie
Šarplaninac (Yugoslavian Shepherd Dog)
Schapendoes
Shetland Sheepdog (Sheltie)
Shiloh Shepherd
Smooth Collie
Spanish Mastiff
Swedish Vallhund
Berger Blanc Suisse
Welsh Corgi (two related breeds)
Welsh Sheepdog
Wyoming Sheepdog